With a variable turbine geometry it is required to exactly define and under certain conditions also limit a minimal flow, wherein this minimal flow corresponds to a corresponding position of the individual guide blades of the variable turbine geometry. Up to now, this is being achieved for example by means of a threaded pin which runs between an actuating device and a link lever of the variable turbine geometry and via which by means of a rotary movement a relative position between the link lever and the actuator can be exactly defined.
From DE 10 2008 049 005 A1 a variable turbine geometry for a charging device, in particular for an exhaust gas turbocharger for a motor vehicle is known, which comprises guide blades that are rotatably mounted in a guide blade ring. For adjusting the guide blades, an adjusting ring is thereby provided, which can be adjusted by an actuator via a link lever. Here, at least one profile is provided on the adjusting ring, which engages in at least one recess on the blade bearing side, wherein the profile interacts with the recess in such a manner that an adjusting movement of the adjusting ring is limited relative to the blade bearing ring and thus for example a minimum flow rate through the variable turbine geometry.
The variable turbine geometries known from the prior art however altogether have the disadvantage that for ensuring or limiting the minimal flow through the variable turbine geometry, comparatively complex limiting devices have to be installed, which in addition require a need for installation space that must not be underestimated.